What was found
LOWER END CAP CORRODED AND 6 RIVET POPPED IN CARGO COMAPARTMENT BELOW CENTER FUEL TANK PRESSURE BULKHEAD. REMOVED DUCT SEAL CONTAINER, DOUBLER AROUND DUCT CUT OUT AND WEB PLUS CORRODED T-CHORD. INSTALLED T-CHORD IAW DC9 SRM, FIG 53-03, PG 15, AND DOUBLER IAW DC9 SRM 51-10-2, AND REINSTALLED DUCT SEAL REATINER IAW DC9 SRM 51-30-1. REPAIR ACCOMPLISHED IAW AEROCORP EO 98-798.